Went to pull my lower timing gear off with a puller. Wasn’t paying atttention and ended up cross threading like the first 6 or so threads. How should I go about tapping it or should I just get a new crank. It’s from a 350
the gear puller was a different thread

 

Seems like you don't have much to lose by retapping it. I would also measure how deep the bolt reaches afterward and maybe buy the longest bolt you can fit before it bottoms out in the crank. A tap will reshape those buggered up threads, but there will be metal missing and you want max thread available for the bolt now.

 

You can try tapping it, sometimes that works. Especially if you can get the tap to follow the original threads.

If not, just Heli-Coil it.

 

If I tap it do I go by the original bolt size or do I go a size over

 

Original

7/16"-14 (std thread) if memory serves.

DO NOT UNDER ANY CIRCUMSTANCES sodomize your crank by forcing some other thread in there.

 

What does std thread mean

 

standard thread
Make sure you use a specific tapping oil or wd40 on the tap too

 

I bought a new Timing set do I honestly need to put the new lower gear on or can I just use the old one and just skip having to take it off

 

You should definitely replace that gear.

You can drill and tap the crank to the Chevy BB size. I have a '70 block in my Jimmy that this was apparently already done to when I got it (no clue why but seems likely that there was some kind of thread malfunctory). Found this out when I swapped balancers, etc. That engine makes about 350 HP with a cam and vortec heads so it doesn't seem to be any issue with upping the bolt size.

GD

 

Well... You should DEFINITELY replace it.. Just sayin'...